Year	Percent
1990	87.046
1991	86.963
1992	86.914
1993	86.75
1994	86.865
1995	87.05
1996	87.112
1997	87.187
1998	87.283
1999	87.372
2000	87.463
2001	87.465
2002	87.408
2003	87.456
2004	87.548
2005	87.687
2006	87.743
2007	87.835
2008	87.891
2009	87.887
2010	87.906
2011	87.878
2012	87.899
2013	87.961
2014	88.033
2015	88.113
2016	88.164
2017	88.215
2018	88.268
2019	88.321
2020	88.376
2021	88.43
2022	88.486
2023	88.541
2024	88.595
2025	88.646
2026	88.694
2027	88.741
2028	88.787
2029	88.83
2030	88.871